报告摘要：LIGO’s first direct detection of gravitational waves in 2015 marked a new era for not just astronomy but also particle physics,  with gravitational waves now becoming a new frontier in particle physics studies, especially in the search for physics beyond the standard model. In this talk, I will firstly give an introduction to the basics of gravitational waves, and briefly go through the various classes of gravitational waves that are currently being searched for at LIGO and by other experiments. I will then discuss the typical sources of gravitational waves in the early universe that are related to particle physics, and the novel ways that gravitational waves have been used to search for dark matter, and highlight the challenges in these studies. The theme of this talk is in line with the Snowmass 2021 white paper "Detection of Early-Universe Gravitational Wave Signatures and Fundamental Physics" (arXiv:2203.07972).